Ammianus, xxx. 10. Zosimus, 1. iv. [c. 19] p. 222, 223. Tillemont has proved (Hist. des Empereurs, tom. v. p. 707-709) that Gratian reigned in Italy, Africa, and Illyricum. I have endeavoured to express his authority over his brother's dominions, as he used it, in an ambiguous style.